Sex differences in ACL loading and strain during typical athletic movements: a musculoskeletal simulation analysis

Female athletes experience anterior cruciate ligament (ACL) injuries at a much greater rate than males, yet the mechanisms responsible for this are not well-understood. The current investigation aimed using a musculoskeletal simulation-based approach, to examine sex differences in ACL loading parameters during cut and hop movements.

Fifteen male and fifteen female participants completed 45° cut and maximal one legged hop movements. Three-dimensional motion capture and ground reaction force data during the stance phase of the cut movement and landing phase of the one legged hop were obtained. Lower extremity muscle forces, ACL forces and ACL strains were extracted via a simulation-based approach using a musculoskeletal model, with an ACL insertion into the femur and tibia.

During the hop movement, females were associated with significantly greater peak ACL forces (male = 15.01 N/kg and female = 15.70 N/kg) and strains (male = 6.87% and female = 10.74%). In addition, for both the cut (male = 4.45 and female = 1.45) and hop (male = 2.04 and female = 1.46) movements, the soleus/gastrocnemius ratio was significantly larger in males.

The current investigation provides new information regarding sex differences during athletic movements that provide further insight regarding the increased incidence of ACL injuries in females.